CN104849618A - Teed line inter-phase fault branch distinguishing method based on power frequency variable quantity - Google Patents

Abstract

The invention discloses a teed line inter-phase fault branch distinguishing method based on the power frequency variable quantity. The method includes the steps of measuring the fault inter-phase voltage power frequency variable quantity and the fault inter-phase current power frequency variable quantity at the protection installation positions of three branches of a teed line, and accurately distinguishing the teed line inter-phase fault branches according to the characteristic that the voltage power frequency variable quantity of an inter-phase short-circuit fault point is the maximum and is decreased monotonically towards the protection installation positions of the three branches of the teed line. The method is applicable to distinguishing fault branches within two cycles after a teed line inter-phase short-circuit fault happens, the distinguishing result is not affected by transition resistance or load current or the fault position, and the teed line inter-phase fault branches can be judged accurately.

Description

Based on the T link phase-to phase fault branch road method of discrimination of power frequency variation

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of T link phase-to phase fault branch road method of discrimination based on power frequency variation.

Background technology

When land resource day is becoming tight, T link due to floor area little, cost is low, has become a kind of common multi-line power transmission mode of electric system.The electric parameters such as voltage transformer (VT), current transformer collecting device is not installed at the T binding place place of T link, after causing T link to break down, need first failure judgement point on any bar branch road of T link, and then utilize two ends of electric transmission line fault distance-finding method to carry out fault localization to abort situation.Therefore, to the correctness of fault branch selection result, direct relation the whether accurate of T link localization of fault.

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence, provide a kind of not by the T link phase-to phase fault branch road method of discrimination based on power frequency variation that transition resistance, load current and abort situation affect.

For achieving the above object, the inventive method adopts following technical scheme:

Based on the T link phase-to phase fault branch road method of discrimination of power frequency variation, it is characterized in that, comprise following sequential steps:

(1) protector measuring T link is at the fault voltage between phases power frequency variation of m end protection installation place with fault three-phase current power frequency variation measure the fault voltage between phases power frequency variation of T link in n end protection installation place with fault three-phase current power frequency variation measure the fault voltage between phases power frequency variation of T link in p end protection installation place with fault three-phase current power frequency variation wherein, φ φ=AB, BC, CA phase;

(2) protective device judges $\left|\frac{{\mathrm{\Δ}\stackrel{\·}{U}}_{\mathrm{m\φ\φ}}-z_1{\mathrm{\Δ}\stackrel{\·}{I}}_{\mathrm{m\φ\φ}}{l}_{\mathrm{mt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{n\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{n\φ\φ}}{l}_{\mathrm{nt}}}\right|>1$ And $\left|\frac{{\mathrm{\Δ}\stackrel{\·}{U}}_{\mathrm{m\φ\φ}}-z_1{\mathrm{\Δ}\stackrel{\·}{I}}_{\mathrm{m\φ\φ}}{l}_{\mathrm{mt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{p\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{p\φ\φ}}{l}_{\mathrm{pt}}}\right|>1$ Set up, then protective device judges that mt branch road is the fault branch of T link; Wherein, φ φ=AB, BC, CA phase; Three branch roads of T link are respectively mt branch road, nt branch road and pt branch road; T is the T binding place of three branch road mt branch roads, nt branch road and pt branch roads; z ₁for unit length electric transmission line positive sequence impedance; l _mtfor the length of T link mt branch road; l _ntfor the length of T link nt branch road; l _ptfor the length of T link pt branch road;

(3) protective device judges $\left|\frac{{\mathrm{\Δ}\stackrel{\·}{U}}_{\mathrm{n\φ\φ}}-z_1{\mathrm{\Δ}\stackrel{\·}{I}}_{\mathrm{n\φ\φ}}{l}_{\mathrm{nt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{m\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{m\φ\φ}}{l}_{\mathrm{mt}}}\right|>1$ And $\left|\frac{{\mathrm{\Δ}\stackrel{\·}{U}}_{\mathrm{n\φ\φ}}-z_1{\mathrm{\Δ}\stackrel{\·}{I}}_{\mathrm{n\φ\φ}}{l}_{\mathrm{nt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{p\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{p\φ\φ}}{l}_{\mathrm{pt}}}\right|>1$ Set up, then protective device judges that nt branch road is the fault branch of T link;

(4) protective device judges $\left|\frac{{\mathrm{\Δ}\stackrel{\·}{U}}_{\mathrm{p\φ\φ}}-z_1{\mathrm{\Δ}\stackrel{\·}{I}}_{\mathrm{p\φ\φ}}{l}_{\mathrm{pt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{m\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{m\φ\φ}}{l}_{\mathrm{mt}}}\right|>1$ And $\left|\frac{{\mathrm{\Δ}\stackrel{\·}{U}}_{\mathrm{p\φ\φ}}-z_1{\mathrm{\Δ}\stackrel{\·}{I}}_{\mathrm{p\φ\φ}}{l}_{\mathrm{pt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{n\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{n\φ\φ}}{l}_{\mathrm{nt}}}\right|>1$ Set up, then protective device judges that pt branch road is the fault branch of T link.

Feature of the present invention and technological achievement:

The inventive method measures the fault voltage between phases power frequency variation of T link three branch protection installation places and fault three-phase current power frequency variation, realizes the accurate differentiation of T link phase-to phase fault branch road according to phase fault point voltage power frequency variation amplitude maximum to T link three branch protection installation place these characteristics of monotone decreasing.The fault branch that the inventive method is applicable in latter two cycle of T link phase fault differentiates, differentiates result not by the impact of transition resistance, load current and abort situation, accurately can judge the phase-to phase fault branch road of T link.

Accompanying drawing explanation

Fig. 1 is the T link transmission system schematic diagram of application the inventive method.

Embodiment

According to Figure of description, technical scheme of the present invention is expressed in further detail below.

Fig. 1 is the T link transmission system schematic diagram of application the inventive method.In Fig. 1, CT is current transformer, CVT is voltage transformer (VT).In the present embodiment, three branch roads of T link are respectively mt branch road, nt branch road and pt branch road, and t is the T binding place of three branch road mt branch roads, nt branch road and pt branch roads.Protector measuring T link is at the fault voltage between phases power frequency variation of m end protection installation place with fault three-phase current power frequency variation measure the fault voltage between phases power frequency variation of T link in n end protection installation place with fault three-phase current power frequency variation measure the fault voltage between phases power frequency variation of T link in p end protection installation place with fault three-phase current power frequency variation wherein, φ φ=AB, BC, CA phase.

Protective device judges and set up, then protective device judges that mt branch road is the fault branch of T link.

Protective device judges and set up, then protective device judges that nt branch road is the fault branch of T link.

Protective device judges and set up, then protective device judges that pt branch road is the fault branch of T link.

Wherein, φ φ=AB, BC, CA phase; Three branch roads of T link are respectively mt branch road, nt branch road and pt branch road; T is the T binding place of three branch road mt branch roads, nt branch road and pt branch roads; z ₁for unit length electric transmission line positive sequence impedance; l _mtfor the length of T link mt branch road; l _ntfor the length of T link nt branch road; l _ptfor the length of T link pt branch road.

The inventive method measures the fault voltage between phases power frequency variation of T link three branch protection installation places and fault three-phase current power frequency variation, realizes the accurate differentiation of T link phase-to phase fault branch road according to phase fault point voltage power frequency variation amplitude maximum to T link three branch protection installation place these characteristics of monotone decreasing.The fault branch that the inventive method is applicable in latter two cycle of T link phase fault differentiates, differentiates result not by the impact of transition resistance, load current and abort situation, accurately can judge the phase-to phase fault branch road of T link.

The foregoing is only preferred embodiment of the present invention; but protection scope of the present invention is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses, the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.

Claims (1)

1., based on the T link phase-to phase fault branch road method of discrimination of power frequency variation, it is characterized in that, comprise following sequential steps:

(1) protective device protector measuring T link is at the fault voltage between phases power frequency variation of m end protection installation place with fault three-phase current power frequency variation measure the fault voltage between phases power frequency variation of T link in n end protection installation place with fault three-phase current power frequency variation measure the fault voltage between phases power frequency variation of T link in p end protection installation place with fault three-phase current power frequency variation wherein, φ φ=AB, BC, CA phase.

(2) protective device protective device judges $\left|\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{m\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{m\φ\φ}}{l}_{\mathrm{mt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{n\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{n\φ\φ}}{l}_{\mathrm{nt}}}\right|>1$ And $\left|\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{m\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{m\φ\φ}}{l}_{\mathrm{mt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{p\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{p\φ\φ}}{l}_{\mathrm{pt}}}\right|>1$ Set up, then protective device judges that mt branch road is the fault branch of T link; Wherein, φ φ=AB, BC, CA phase; Three branch roads of T link are respectively mt branch road, nt branch road and pt branch road; T is the T binding place of three branch road mt branch roads, nt branch road and pt branch roads; z ₁for unit length electric transmission line positive sequence impedance; l _mtfor the length of T link mt branch road; l _ntfor the length of T link nt branch road; l _ptfor the length of T link pt branch road.

(3) protective device judges $\left|\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{n\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{n\φ\φ}}{l}_{\mathrm{nt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{m\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{m\φ\φ}}{l}_{\mathrm{mt}}}\right|>1$ And $\left|\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{n\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{n\φ\φ}}{l}_{\mathrm{nt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{p\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{p\φ\φ}}{l}_{\mathrm{pt}}}\right|>1$ Set up, then protective device judges that nt branch road is the fault branch of T link;

(4) protective device judges $\left|\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{p\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{p\φ\φ}}{l}_{\mathrm{pt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{m\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{m\φ\φ}}{l}_{\mathrm{mt}}}\right|>1$ And $\left|\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{p\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{p\φ\φ}}{l}_{\mathrm{pt}}}{\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{n\φ\φ}}-z_1\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{n\φ\φ}}{l}_{\mathrm{nt}}}\right|>1$ Set up, then protective device judges that pt branch road is the fault branch of T link.